The subject matter described herein relates to electrical power distribution, and more particularly to intelligent microgrids which may be deployed alone or in combination to distribute electrical power.
Existing microgrid distribution systems are essentially disconnected islands at a facility or in an electrical distribution system that contain at least one distributed resource and associated loads. These microgrids may be connected to a broader utility grid, but in instances like blackouts, these microgrids switch to backup mode, disconnect from the utility, and continue to generate electricity to specific loads.
For such microgrids to work properly, a switch opens during upstream conditions, and the energy resources must be able to carry the load on the islanded section. This includes maintaining suitable voltage and frequency levels for all loads in the island served by the microgrids. Depending on the switch technology utilized, momentary interruptions may occur during transfer from grid-connected to power back-up mode.
More recent applications include hybrid islanded microgrids which combine renewable energy sources and diesel generators, with or without storage batteries. However, injecting renewable energy resources on a diesel-powered isolated grid does not yield a large positive impact, as diesel generators perform poorly at partial load. One alternative is to allow the renewable energy resources, with energy storage components, to stop the generators periodically. This approach will immensely reduce both the cost and the carbon footprint of the generator in the environment.
In short, existing microgrids are not intended to work in an isolated grid architecture where two or more of these resources are paralleled and one of these resources acting as the primary power source. The drawback is a technically complex power interface associated with load sharing, power quality, and synchronization of power supplied.
Accordingly, there remains a need in the art for an innovative power interface and associated control system for a smart, robust microgrid architecture that provides a high level of flexibility and adaptability, and that can operate in either grid-tied or isolated grid mode.